Graphene-based magnetoelastic biosensor for COVID-19 serodiagnosis

TL;DR

This study develops a graphene-based magnetoelastic biosensor for rapid, sensitive, and low-cost COVID-19 antibody detection, demonstrating effective differentiation between positive and negative plasma samples with potential for point-of-care use.

Contribution

It introduces a novel graphene functionalization method for magnetoelastic biosensors, enhancing sensitivity and reproducibility in COVID-19 serodiagnosis.

Findings

Successfully detected COVID-19 antibodies in human plasma samples.

Validated sensor performance with ELISA comparison.

Achieved high sensitivity and specificity with optimized biofunctionalization.

Abstract

This work presents an innovative magnetoelastic (ME) biosensor using graphene functionalized with the SARS-CoV-2 N protein for antibody detection via magnetoelastic resonance. Graphene was chosen for its biocompatibility and high surface area, enabling efficient antigen adsorption, validated by techniques such as energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and micro-Raman spectroscopy. Changes in Raman bands (a $\sim 10~\mathrm{cm}^{-1}$ shift in the 2D band and an increase in the $I_D/I_G$ ratio from 0.03 to 0.60) confirmed non-covalent interactions and enhanced surface coverage with ~100 $\mu$g of N protein. Tests using human plasma (10 RT-PCR-positive and 10 negative samples) demonstrated a clear distinction between groups using graphene sensors functionalized with ~100 $\mu$g of N protein. Enzyme-linked immunosorbent assay (ELISA) validation corroborated the results. Optimization of protein concentration and biofunctionalization time highlighted the importance of homogeneous surface coverage for reproducibility of the graphene-based ME biosensor. The platform combines graphene's advantages with the wireless, real-time detection capabilities of ME sensors, offering low cost, high sensitivity, and potential for automation, with applications in point-of-care diagnostics.